1. Field of the Invention
The present invention relates to methods for manufacturing semiconductor devices having semiconductor elements.
2. Description of the Related Art
In a conventional manner, so-called active matrix driving type display panels or semiconductor integrated circuits which are constituted by semiconductor elements such as thin film transistors (hereinafter also referred to as TFTs) or MOS thin film transistors are manufactured by formation of a resist mask by a photolithography process using a photomask and a selective etching process of each thin film.
In the photolithography process, resist is applied to the entire surface of a substrate, pre-baked, and subjected to ultraviolet rays or the like through a photomask to expose a pattern of the photomask to light. The pattern is developed and washed with pure water to form a resist mask. Then, a thin film (a thin film formed of a semiconductor material, an insulator material, or a conductor material) except for portions which are to be serve as a semiconductor layer or wirings is etched using the resist mask as a mask to form the semiconductor layer or the wirings.
The applicant discloses a technique in Japanese Patent Application No. S63-84789. The technique is a thin film processing method in which a light-transmitting conductive film is irradiated with a linear laser beam having a wavelength of 400 nm or less to form grooves.
Japanese Published Patent Application No. H 9-152618 discloses a thin film processing technique in which a light-transmitting film is irradiated with a linear laser beam so that the light-transmitting film is ablated and removed (ablation) instantaneously to be patterned.